In manufacturing a wafer having a thin plate shape from a columnar workpiece through cutting using wire electric discharge machining, in order to improve productivity of the cutting, there has been proposed a system for repeatedly winding one wire over a plurality of guide rollers to simultaneously perform machining using a large number of wires. In a wire electric discharge machining apparatus of this system, cutting wire sections in which wires are disposed in parallel at a fixed pitch are formed, the cutting wire sections are brought close to a workpiece and power is fed individually to the respective wires, which configure the cutting wire sections, using power feed elements to cause electric discharge simultaneously and in parallel between the cutting wire sections and the work piece and perform the cutting in parallel in a plurality of places (see, for example, Patent Literature 1).